Thermal insulation structure



June '16, 1936. J. M. LE GRAND I THERMAL INSULATION-STRUCTURE 8Sheets-Sheet 1 Filed Feb. 7, 1934 7 J55 72 M is Grma Mfl Q 49 EN-w I1936- J. M. LE GRAND 2,044,731

THERMAL INSULATION STRUCTURE Filed. Feb. 7, 19354 Z-+- 42 8 Sheets-Sheet2 J i fiu/xznfor JSQ U LM 152 G ana! Junev 16, 1936. J. M. LE GRAND 3THERMAL INSULATION STRUCTURE I Filed Feb. '7, 1954 s Sheets-Sheet slid/2772507 r39 .fos piz/flle (fr and @ww QW June 16, 1936. J M LE GRAND2,044,731

THERMAL INSULAT ION STRUCTURE Filed Feb. 7, 1934 8 Sheets-Sheet 4iii/75607 fis/gpfijk/fle Gin/ml June 16, 1936.

J. M. LE GRAND THERMAL INSULATION STRUCTURE Filed Feb. '7, 1934 8Sheets-Sheet 5 7LM Le Grand fill/07716.07

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June 16, 1936. J, LE GRAND 2,044,731

THERMAL INSULATION STRUCTURE Filed Feb. '7, 1934 8 Sheets-Sheet 6 92 94J05 J06 J07 92 J 9 J07 05 J06 J06 J05 \AJ r Mantow .fasxz izflfle Grand11 u e 16, 1936. J LE GRAND 2,044,731

THERMAL INSULATION STRUCTURE Filed Feb. '7, 1934 8 Sheets-Sheet 7 91 J05J06 J07 J04 J01 J05 J06 J07 .fos/gp/a M Z1), GPMLZ Jun 16, 1936. v1M. LEGRAND 2,044,731

THERMAL INSULAT ION STRUCTURE Filed Feb. '7, 1934 I 8 Sheets-Sheet 8Patented June to, Test UNITED STATES attain 2,044,731 THERMAL INSULATIONs'muo'roan 28 Claims.

My invention relates generally to thermal insulation and it has to domore particularly with structure adapted to insulate against thetransfer of heat through a space bounded by relatively higher, and lowertemperature areas.

One of the objects of the invention is to provide an improved structureof the foregoing char acter which is simple in construction, is easy andinexpensive to manufacture, is light in weight,

and which insures high insulation efllciency at,

low cost to the user.

Another object is to provide an improved insulation structure embodyingthermal insulation features disclosed in Letters Patent 1,910,703,

granted to me on May 23, 1933.

. A further object is'tc provide an improved allmetal insulationstructure which is practically free from condensation efiects, moistureabsorption eiiects and other objectionable psychrometric conditions;which insures substantially uniform insulation effect throughout theentire structure insulated; and which is strong and durable and insuressubstantially uniform and maximum insulation results for the life of thestructure insulated.

An additional object is to provide a closed insulating unit ofpackage-like form which is light in weight, which may be easily andquickly applied to and removed from the structure to be insulated, andwhich may be readily packed and shipped. Still another object is toprovide an insulation structure including a plurality of units soconstructed and arranged that they find support upon the walls definingthe space to be insulated, the arrangement being such that heat loss byconduction through the points of support and through the unit as a wholeis reduced to the minimum. a

A more specific object is to provide an insulating unit consisting of aplurality of spaced sheets formed of a material possessing relatively.low reflective characteristics when exposed to radiation of Wavelengths within the visible portion of the electromagnetic spectrum andrelatively high'reflective characteristics when exposed to radiation oflonger wave lengths than the Ivisible portion of the electromagneticspectrum, said sheets being held in desired spaced relation with respectto each other and the wall surfaces defining the 50 space to beinsulated by members formed of a metallic material of relatively lowheat condu tion capacity which are connected to said sheets at spacedpoints around the latter.

An additional object is to provide a unit of the foregoing characterwherein the edges of the Joseph M. Le Grand, Hcathsville, Va.Application February '1. 1934, Serial No. 110,131

sheets throughout the width of the unit are bounded by a sheet ofrelatively thin, non-heatconducting material, whereby the air spacesformed by said sheets and the wall surfaces de- 7 fining the space to beinsulated are sealed apart 5 from each other and from the air spaces ofadjacently disposed units.

Other objects and advantages will become apparent as this descriptionprogresses and by reference to the drawings wherein,-'- 10 Figure 1 isan elevational sectional view through one form of structure embodying myinvention, said view being taken substantially on line ll of Fig. 2;

, Fig. 2 is an elevational sectional view taken 15 substantially on line2-2 of Fig. 1;

Fig. 3 is an enlarged plan sectional view taken substantially on line 33of Fig. 1;

Fig; 4 is .an enlarged perspective view of one of the insulation unitsshown in the previous 20 figures, certain portions thereof being cutaway and shown in section to more clearly illustrate the structure;

Fig. 5 is a section taken taken substantially on line 5-5 of Fig. 4;

Fig. 6 is a perspective view oi another form of insulating unitembodying my invention, certain of the parts of the same being cut awayand shown in section; 1

Fig. 'l is a fragmental sectional view of awalled 30 structure, such asthat shown in Fig. 1 illustrat ing units of the form of Fig. 6 appliedthereto for insulation purposes;

Fig. 8 is an elevational sectional view of another form of structureembodying my invention; 5

Fig. 9 is an enlarged plan sectional view taken substantially on line9-9 of Fig. 8;

-Fig. 10 is an enlarged iragmental perspective view of a corner portionof the form of unit shown in Figs. 8 and9;

Fig. 11 is a section taken substantially on line ll-H of Fig. 10; and

Fig. 12 is an enlarged perspective view of one of the units shown inFig. 9, certain of the partsthereof being cut away and shown in section.

In the drawings .1 have illustrated my invention as applied to,different forms of household refrigerator cabinets. It is to beunderstood, however, that my invention is not limited to this particularuse but that it has utility in numerous 60.

other instances where the advantages and results aiiorded'thereby aredesired; such, for ex-- ample, as various other kinds of refrigerators,ice boxes, refrigerator-cars, cold storage vaults, furnaces, boilers,buildings, ovens, driers, 55

hot rooms, railway cars, automotive vehicles, spray booths, air craft,vessels, etc.

The cabinet structure shown in Figs. 1 to 5, inclusive, takes the formof an outer shell 20 of rectangular shape in cross section and asimilarly-shaped inner shell 2| defining a substantially continuous wallspace 22 extending around the top, bottom side and rear walls of thecabinet. The vertical walls of the outer shell 20 are extendeddownwardly beneath its bottom, as at 23, to receive legs 25, forsupporting the cabinet in an upright position. The front walls of boththe inner and outer shells are provided with aligned openings (the outerof which is larger) surrounded, respectively, by flanges 25 and 25.which are joined together by a facing strip 21 which serves to support,in part, the shells 20, 2| in spaced relation with respect to each other,The facing strips 21 extend entirely around the shell open ings anddefine a rather deep and wedge-shaped doorway through which access isbad to the interlor of the inner shell 2| which serves as a refrigeratorcompartment '28.

The door opening is adapted to be closed by a shell-like door comprisingan inner wall 29'jand an outer well, both. of .which areprovided withperipheral flanges to which facing strips 3| are secured to space apartthe walls 29 and 30 and to provide an enclosed shell structure. The dooris provided along one vertical edge with hinge structure 32, and alongits opposite edge with suitable latch means (not shown) whereby the doormay be opened and closed and latched in. a manner which will be wellunderstood. The outer door wall 35 is slightly larger than the outerpart of the door opening so that it overlaps the outer shell wall 20around the door opening. A bumper strip 32 formed of rubber, or othersuitable material, is carried by the overlapping edge of the outer doorwall 30 so that a substantially sealed closure will be effected when thedoor is closed and latched.

Thermal insulation means constructed and arranged in accordance with myinvention is mounted within the cabinet wall space 22 and within thedoor space. This insulation means takes the form of a plurality of unitsof package-like form whichare mounted within the space 22 in abuttingrelation with respect to each other and the inner and outer shell walls2|, 20. A single unit of this form is mounted within the door.

The insulation structure includes side wall units 40, rear wall unit 4|,top unit 52, bottom unit 45 and door unit 44. These several units differsomewhat in outline dimensions to suit the dimensions of the particularwall space in which they are mounted; however, all of these units are ofthe same general form and construction and only one of them, therefore,will be described in detail.

The insulation unit (Fig. 4) comprises a plurality of metallic sheets50, 5| and 52 which have the thermal insulation characteristics andproperties disclosed in my said Letters Patent No. 1,910,703. Moreparticularly, these sheets are formed of a material of sufficientthickness and stiffness to retain preformed shape; which material alsopossesses relatively low reflective characteristics when exposed toradiation of wave lengths within the visible portion of theelectromagnetic spectrum and relatively high reflective characteristicswhen exposed to radiation of longer wave lengths than the visibleportion of the electromagnetic spectrum. One material which possessesthese characteristics. and which I preferably employ, is commercialblack steel. This material is of a dull non-bright character whichreflects a low percentage of visible light as distinguished from brightsurfaces or materials such as aluminum foil, tin foil, etc. It will beunderstood, however, that, so far as certain of the structural featuresof my invention are concerned, any suitable material adapted to giveadequate insulation value under the existent conditions of use may beemployed without departing from my invention.

The metallic sheets 50, 5|, and 52 are also,

preferably, spaced apart in parallel relation in the manner taught by myaforesaid prior patent. That is to say, the sheets are so spaced apartthat sheet 50 is located quite close to the outer shell 20 (or thehigher temperature wall surface) and the other sheets are spacedprogressively farther apart toward the inner shell 2| (or the lowertemperature wall surface). Also, the sheets are so spaced with respectto the higher temperature wall surface that the central plane of thegroup of sheets is closer to the outer shell 25 orhigher temperaturewall) than to the inner shell 2| (or lower temperature wall) and thiscentral plane is spaced from the outer shell a distance which fallswithin the dimensional limits of less than one-half and more thanone-third of the distance between the inner and outer shells 20 and 2|or the space-defining wall surfaces.

Each metallic sheet of the unit is of pan-like shape, having anangularly-disposed peripheral flange'53therearound. Each sheet,.inaccord with the teaching of my prior Patent No. 1,910,- 703, ispreformed to'divide its body surface into a plurality of angular andintersecting plane surfaces 54, and alternately directed ribs 55 areprovided at the intersections of the plane surfaces 54. By thus formingthe sheet, the insulation efllciency of the unit is increased, thepropagation of sound waves by vibration of the sheets is prevented andadditional strength and rigidity is provided for in the sheet per se andin the unit as a whole.

The unit employed in the form of Figs. 1 to 5, inclusive, ismiter-shaped being provided with mltered side edges so that, when theseveral units are assembled within the wall space 22 in abuttingrelation with respect to each other, a strong and substantially rigidstructure will be provided for. In forming the miter-shaped unit, suchas the unit 40 shown in Fig. 4, the sheets 50, 5|, and 52 are,respectively, of progressively decreasing size so that when they arejoined together in substantially parallel relation in unit fashion, thesides of the unit will be disposed at substantially 45 degrees withrespect to the planes of the sheets.

The several sheets 50, 5|, and 52 are joined together in the spacedrelation hereinabove more particularly set forth by angled spacingmembers 56 located at the corners of the sheets. These spacing membersare, preferably, formed of a high chrome nickel alloy which possessesapproximately only one-third of the heat conduction ability of thematerial from which the sheets 50, 5|, and 52 are formed. The cornerportions 51 of the metallic sheets (Fig. 5) which receive the angledspacing members 56 are countersunk at 58 so that the outer surfaces ofthe spacing members 56 will lie substantially flush with the outersurfaces of the sheet flanges 53. The spacing members 56 are,preferably,

secured to the sheet flanges by spot welding in any suitable fashion.For example, the several sheets and spacing members may be assembled ina welding rack or jig which is shaped and sized to receive thedifferent-sized sheets and to hold them in the proper spaced relation.The welding structure may be such that all of the "sheets and spacingmembers may be welded at a single welding operation; or if desired, thespacing members may have tongues struck out therefrom in planes parallelwith the planes of the sheets 53 in such positions as to properly spacethe sheets apart, such tongues being welded, or otherwise secured, tothe sheets to hold members 56 beyond the sheets determines the extent towhich the plane surfaces of the sheets are spaced from the shell wallsor surfaces de-.

fining the space to be insulated. In certain instances where the unitsare of considerable length, as for example, the side units 40, it may bedesirable to employ additional edge supporting means to insure thedesired rigid unit arrangement. To this end, I may employ intermediatestrips or members 59 (Fig. 4) which are of the same material and aresecured to the edge flanges 53 of the metallic sheets in the same manneras the corner members 56. These intermediate members 59 are also of thesame length as the corner members 56 so that they abut the wall surfacesand insure the proper positioning Y of the intermediate portion of theunit within the space to be insulated.

In further carrying out my invention, it is desirable that the airspaces between the several metallic sheets be positively sealed fromeach other for reasons which will be well understood from my aforesaidprior patent. To that end, I, therefore, cover the miter edges of theunit with paper 60 or other suitable non-heat-conducting material. Ihave found that a gummed asphalt paper well serves this purpose. Amineral adhesive is applied to one side of the paper so that it willadhere to the outer surfaces of the sheet flanges 53 and the spacingmembers 56 and 59. The sheet of paper 50 is of a width substantiallyequal to the length of the spacing members and 59 so that not only thespaces between the sheets 50, 5i, and 52 are sealed, but also the spacesdefined by the sheets 50 and 52 and their adjacent wall surfaces (shells20 and 21) are likewise sealed from the spaces between the sheets. i

'portion of the rear wall unit 4i and the rear edge portion of thebottom unit 43. In this manner, the bottom unit serves, in eil'ect, as asupport for the side and rear units. The mitered edges of the top unit42 abut the adjacent edges of the side and rear units 40 and 4i and thevertical mitered edges of the side units 40 abut the complementalvertical mitered edges of the I rear unit 4!, so that when all of theinsulating units are assembled within the cabinet walls, a comparativelysolid block-like structure is provided. The paper binding strip 60around the several units serves to space apart the metallic surfaces ofthe units at the points where they abut each other, as well as to sealthe air spaces of one unit from the air spaces of adjacent units. Thedoor insulation unit 45 is of the same gen eral shape as the othercabinet wall units and it finds support upon the inner and outer doorwalls 29 and 30 in the same manner that the other units find supportwith respect to their adjacent wall surfaces.

When the units are thus assembled within the cabinet structure, it willbe seen that the metallic sheet 50 of each unit is located comparativelyclose to the outer shell wall 25 or outer door wall 30, as the case maybe. and that the other sheets bear the spaced relationship with respectto each other and to the shell walls which I have pointed out moreparticularly hereinbefore. They provide, in conjunction with the shellwalls 20, 2|, a plurality of uni-planar unobstructed insulat ing spacesll, 52, 53, and 54 along the several walls of the cabinet which aresubstantially free from connection currents.

It is to be understood that, while I have found that in certainstructures and in insulation spaces of certain widths three metallicsheets well serve the purpose, the number of metallic sheets may bevaried without departing irom my invention. If the number of sheets isincreased or diminished, I preferably-mount and space the same in themanner hereinabove described; and the unit, except for the number ofsheets, remains substantially of the same construction as alreadydescribed.

In some instances, it may be desirable to em-' ploy a unit wherein theseveral sealed air spaces corresponding to the spaces BI, 52, 63, and 64of the form of Figs. 1 to 5, inclusive, are fully enclosed within theunit. In that case I preferably employ the structure illustrated inFigs. 6 and '7.

Specifically, the unit 15 (Fig. 6) is similar in all respects to theunit 40 of Fig. 4 except that metallic outer seal plates II and 12 areemployed. These seal plates are of the same outline shape as the metalinsulation sheets 13, I4, and 15 and they may be formed of the samemetallic material as sheets I3, 14, and 15. Also, these seal plates maybe plain-surfaces or ribbed, as desired. All of the sheets and plates ofthe unit are provided with angled edge flanges 16 to which high chromenickel alloy members 11 are secured for holding the same in the desiredsubstantially parallel and spaced relationship.

When the unit 10 is placed in the space to be insulated (Fig. '1), theouter plate 12 seats against the higher temperature or outer wall 18 andthe other outer plate. Ii seats against the lower temperature or innerwall 19. When several units 10 are assembled in the space to,beinsulated they bear the same relationship to each other as do thepreviously described units. Heat loss by conduction, regardless of thekind of materialfrom which the walls 18 and 19 are formed, is kept atthe minimum since the several sheets and plates are connected only bythe low heat conducting spacing members 11.

Another form of cabinet structure which is well suited for householdrefrigerator purposes,

and to which my invention may be applied, is illustrated in Figs. 8 to12 inclusive. Specifically, this cabinet structure takes the'form ofinner and outer shells and ill of rectangular shape in cross-section andformed, preferably, of metal. The inner and outer shells are spacedapart and supported by horizontal girts 92 and vertical posts 93 (Fig.9) which together with theinner and outer shells 90 and SI, a top plate94 and a bottom plate 95 define side, rear, top and bottom spaces 96,91, 98, and 99. The girts' and posts are formed, preferably, of afibrous or the like material, which has comparatively low heatconduction capacity.

The door opening of this cabinet structure, and the door I00 for closingthe same, are formed like those shown in Fig. 3. The space defined bythe inner and outer door walls IM and I 02 receives vertical posts I03and horizontal girts (not shown) which form an insulation space I04similar to the insulation spaces formed in the cabinet walls.

The cabinet wall spaces 96, 91, 98, and 99 receive insulation unitswhich are similar to the unit of Fig. 4, except that they are ofrectangular-shape in cross section instead of miter-shape. In this formof unit (Fig. 12), the sheets I05, tilt, and Bill are all the same size,each being provided with a substantially right-angled peripheral flangeI08. The sheets are supported as a unit in spaced relation by angledcorner members I09 which are fitted in countersunk corner portions II 0of the sheet so that their outer surfaces lie flush with the outersurfaces of the sheet flanges I08. Each of, the corner members I09 isprovided with a plurality of struck-out tongues Ii i along its lengthand at such positions that, when the sheets are seated thereon, as shownin Fig. 11, the sheets are spaced apart the desired distance asexplained in connection with the previously-described forms of myinvention. The tongues III may be welded, or otherwise secured to thesheets to effect the permanent assembly of the parts. If desired, thetongues ill may be omitted and the sheets may then be secured to thecorner members I09 by welding as in the previously-described form. Or,tongues may be struck out from the sheet flanges I00 and interlockedwith the corner members I09 in any desired manner, as by clinching,welding, etc. Intermediate support members II2 may be employed, if thatis found desirable. These intermediate pieces are applied and secured inthe same manner as the corner members I09 or in the manner described inconnection with the members 59 of Fig. 4. Both the corner andintermediate spacer members are formed, preferably, of high chromenickel alloy to minimize heat loss by conduction through these pieceswhich abut the inner and outer shells 90, 9| as in the previous form.The units are of such size that they fit snugly within the wall and doorspaces 96, 91, 98, 99, and I04. Other than above described, this form ofunit is of the same construction and arrangement as thepreviously-described units.

I believe that the operation, as well as the features and advantages, ofmy invention will be readily understood from the foregoing. Thearrangements described provide for the near maximum insulation againstthe transfer of heat by re.- diation, convection, and conduction. Thestructure employed is quite simple, inexpensive materials are employed,and the units may be cheaply manufactured: thereby reducing the cost ofinsulated structures to the user. The packageform insulating units arelight in weight and they may be easily and quickly installed. In the useof my invention, very light and inexpensive cabinet structures may beemployed, the insulation structure being of such character as to givestrength and rigidity to the structure as a whole. Heat loss byconduction through the units is reduced to the very minimum, due to theuse of a very few supporting and connecting members which are ofthemselves low heat conductors. The structure is very durable and willfunction with substantially uniform efficiency throughout the life ofthe cabinet structure. The space insulated, in the use of my invention,remains practically free from condensate and the detrimental efiectsthereof. There are no parts in the insulation structure which willdeteriorate and materially affect the insulation eillciency of thestructure as a whole.

It is to be understood that while I have shown and described severalforms of my invention, other changes in details and arrangements ofparts may be made without departing from the spirit and scope of myinvention as defined by the claims which follow.

I claim:

1. In structure of the class described, a pinrality of walls each formedby spaced wall surfaces deflning a space to be insulated, and means forthermally insulating each of said walls which comprises a plurality ofspaced metallic sheets of suillcient thickness and stiflness to retainpreformed shape, said sheets being so arranged that the sheet next tothe higher temperature wall is comparatviely close thereto and the othersheets are spaced progressively farther apart toward the lowertemperature wall, means located at spaced points around the periphery ofsaid sheets and secured to said sheets for holding said sheets in saidspaced relation, said means including members engaging said wallsurfaces and for supporting said sheets as a unit upon said wallsurfaces, and means formed of non-heat-conducting ma.- terialmountedupon the peripheral edges of said sheets and upon said spacing means forsealing apart from each other the spaces between said sheets and betweensaid sheets and wall surfaces.

2. In structure of the class described, a plurality of walls each formedby spaced wall surfaces defining a space to be insulated, and means forthermally insulating each of said walls which comprises a plurality ofspaced metallic sheets which are formed of a material possessingrelatively low reflective characteristics when exposed to radiation ofwave lengths within the visible portion of the electromagnetic spectrumand relatively high reflective characteristics when exposed to radiationof longer wave lengths than the visible portion of the electromagneticspectrum, and means located at spaced points around the periphery ofsaid sheets and secured to said sheets for holding said sheets in spacedrelation, said means including members engaging said wall surfaces andfor supporting said sheets as a unit upon said wall surfaces.

3. In structure of the class described, a plurality of walls each formedby spaced wall surfaces defining a space to be insulated, and means forthermally insulating each of said walls which comprises a plurality ofspaced commercial black steel sheets, means located at spaced pointsaround the periphery of said sheets and secured 75 to said sheets forholding said sheets in spaced relation, said means including membersengaging said wall surfaces and for supporting said sheets as a unitupon said wall surfaces, and means mounted over the edges of said sheetsfor sealing the spaces formed by said sheets and walls from each other.

4. In structure of the class described, a plurality of walls each formedby spaced wall surfaces defining a space to be insulated, and means forthermally insulating each of said walls which comprises a plurality ofspaced metallic sheets arranged in group form, means located at spacedpoints around the periphery of said sheets and secured to said sheetsfor holding said sheets in such spaced relation that the central planeof the group df sheets is spaced from the higher temperature wall adistance which falls within the dimensional limits of less than one-halfand more than one-third of the distance between said space-defining wallsurfaces, said means including members engaging said wall surfaces and.for supporting said sheets as a unit upon said wall surfaces, andnon-heat-conducting means extending around the edges of said sheetssealing apart from each other the spaces formed by said sheets andwalls. I

5. In structure of the class described, a plurality of walls formed byspaced wall surfaces defining a space to be insulated, and means forthermally insulating said space which comprises a. plurality ofmiter-shaped units each including a plurality of spaced metallic sheetswhich together with said space-defining wall surfaces define a pluralityof air spaces, means surroimding the edges of said units for sealingsaid air spaces apart from each other, said units being so arranged thatthe miter edges of adjacent units abut each other, and means for spacingsaid sheets which also abuts the adjacent space-defining wall surfacesfor support of said units in said space to be insulated.

6. In structure of the class described, a pinrality of walls formed byspaced wall surfacesdefining a space to be insulated, and means forthermally insulating said space which comprises 7 a plurality ofmiter-shaped units each including sulating said units from each other.

7. In structure of the class described, a plurality of walls formed byspaced wall surfaces defining a space to be insulated, and means forthermally insulating said space which comprises a plurality ofmiter-shaped units each including a plurality of spaced metallic sheetswhich together with said space-defining wall surfaces define a pluralityof disconnected air chambers, the arrangement being such that the miteredges of adjacent units abut each other, means secured to said units forsupport of said units in said spaceto be insulated, and a thin sheet ofpaper material adhesively secured around the miter edges of said unitsthroughout the width of the letter, inclusive of said support means,sealing the air chambers of each unit apart from each other and apartfrom the air chambers of adjae cent units and preventing metalliccontact between abutting units. 5

8. In structure of. the class described, spaced wall surfaces defining aspace to be insulated, and means for insulating said space whichcomprises a unit including a plurality of spaced metallic sheets mountedsubstantially parallel with each 10 other and said wall surfaces, aplurality of spacer members of a length substantially equal to thedistance between said wall surfaces and to which the edge portions ofsaid sheets are secured for holding said sheets in said spaced relationand in spaced relation to said wall surfaces, and a thin covering overthe edges of said sheets and said spacer members sealing apart from eachother the air spaces formed by spacing said sheets from each other andsaid wall surfaces.

9. In structure of the class described, spaced wall surfacesdeflning aspace to be insulated, means for insulating said space which comprises aunit which includes a plurality. of metallic sheets the outer of whichare adapted to seat against said wall surfaces with the intermediatesheets spaced from each other and from said outer sheets, spacingmembers located at spaced points around and secured to the edge portionsof said sheets for holding them insaid spaced relation,and a thinnon-heat-conducting covering around the edges of said sheets sealing theair spaces therebetween apart from each other.

10. In structure of the class described, means including a. pair ofsubstantially parallel spaced wall surfaces defining a closed space ofsubstantially rectangular outline shape, and means for insulating saidspace which comprises a unit of substantially the size and shape of saidspace mounted in the latter, said unit including a plurality of spacedmetallic sheets of substantially the outline shape and dimensions ofsaid space, means for holding said sheets in spaced relation withrespect to each other and said wall surfaces, and a thinnon-heat-conducting material secured around the edges of said sheetssealingthe spaces between said sheet and said wall surfaces apart fromeach other and also holding said sheet edges out of contact with saidspace-defining means.

11. In structure of the class described, means including a pair ofsubstantially parallel spaced wall surfaces defining a closed space ofsubstantially rectangular outline shape, and means for insulating saidspace which comprises a unit of substantially the size and shape of saidspace mounted in the latter, said unit including a plurality of spacedmetallic sheets ofsubstantially the outline, shape and dimensions ofsaid space,

spacer strips mounted at intervals around and 60 secured to the edgeportions of said sheets for holding said sheets in spaced relation withrespect to each other and said wall surfaces, and a thin paper coveringsecured around the edges of said sheets sealing the spaces between saidsheet and said wall surfaces apart from each other and also holding saidsheet edges out of contact with said space-defining means.

12, In structure of the class described, vertical posts, horizontalgirts, wall members supported by said posts and girts to define a closedspace to be insulated, and means for insulating said space whichincludes a unit of the outline shape of said space adapted to fittherein, said unit including a plurality of metallic sheets, spacermembers secured around the edges of said sheets sheets in apredetermined spaced relation with respect to each other and said wallmembers, and means extending around the edges of all said sheets forsealing the spaces between said sheets and wall members from each otherand for preventing contact between said sheets and said posts and girts.

13. A thermal insulation unit which comprises I a plurality of metallicsheets of suflicient thickness and stifiness to retain pre-formed shape,means located at spaced points around said sheets for fixedly supportingsaid sheets in a predetermined spaced relation with respect to eachother, and a thin covering secured to .the edges of said sheets sealingthe air spaces therebetween apart from each other and concealing saidsupporting means.

14. A thermal insulation unit which comprises a plurality of metallicsheets, spacing members located at spaced points around the peripheraledges of said sheets and to which said sheets are secured for fixedlysupporting said sheets in a predetermined spaced relation, said membersprojecting beyond the planes of the outermost of said sheets forsupporting said sheets as a unit in a space to be insulated, and a thincovering of non-heat-conducting material secured to the edges of saidsheets and to said members sealing the air spaces formed bysaid sheetsapart from each other.

15. A thermal insulation unit which comprises a plurality of metallicsheets of rectangular shape and of suflicient thickness and stifiness toretain pre-formed shape, spacing members connected to the corners ofsaid sheets and projecting beyond the planes of the outermost sheets forholding said sheets as a unit in predetermined spaced relation withrespect to each other and the surfaces defining the space to beinsulated, and a. covering secured over the edges of said sheets andover said spacing members. 1 g

16. A thermal insulation unit which comprises a plurality of spacedmetallic sheets having normally a high heat .conduction capacity and ofsufiicient thickness and stiffness to retain preformed shape, spacingmembers-formed of a high chrome nickel steel alloy materialsecured tosaid sheets at spaced points around the edges thereof, and a relativelythin and non-heat-conducting covering secured over the edges of saidsheets sealing the spaces between said sheets apart from each other. A

17. A thermal insulation unit which comprises a plurality of spacedmetallic sheets having normally a high heat conduction capacity, spacingmembers formed of a high chrome nickel alloy material of low heatconduction capacity secured to the corner portions of said sheets forholding the latter in a predetermined spaced relation, other spacingmembers of similar material connected to the edge portions of saidsheets intermediate of and spaced from said corner spacing members, anda covering formed of a non-heatcondueting material secured over theedges of said sheets.

18. A thermal insulation unit which comprises a plurality of stiffspaced metallic sheets having normally a high heat conduction capacity,spacing members secured to said sheets for holding the latter in apredetermined spaced relation, all of said spacing members beingcountersunk within the edge portions of said sheets so that their outersurfaces are substantially flush with the edge surfaces of said sheets,and a thin non-heatconducting covering secured over said sheet edges andsaid spacing members to seal the spaces between said sheets apart fromeach other.

19. A thermal insulation unit which comprises a plurality of stiffmetallic sheets having edge flanges giving the same a pan-shape, spacedmembers against which said flanges seat for securing said sheets in apredetermined spaced relation, and a comparatively thin coveringextending 0 around' the edges of said sheets and secured to said flangesfor sealing apart from each other the spaces between said sheets.

20. A thermal insulation unit which comprises a plurality of stiffmetallic sheets having edge 15 flanges giving the same a pan-shape,spacing members against which said flanges seat for secura plurality ofstifi metallic sheets normally of comparatively high heat conductioncapacity, a 30 plurality of means spaced apart and of comparatively lowheat conduction capacity for spacing said sheets predetermined distanceswith respect to each other and surfaces defining the space to beinsulated, and non-heat-conduction means 3 covering the edge portions ofsaid sheets and the spaces therebetween for sealing apart from eachother the spaces defined by said sheets. Y

22. A thermal insulation unit which comprises a plurality of metallicsheets of sufilcient thick- 40 ness to'maintain preformed shape andformed of a material possessing relatively low reflectivecharacteristics when exposed to radiation of wave lengths within thevisible portion of the electromagnetic spectrum and relatively highreflective 45 characteristics when exposed toradiation of longer wavelengths than the visible portion of the electromagnetic spectrum,metallic members of relatively low heat conduction capacity secured atspaced points to said sheets to space the latter 59 in a predeterminedmanner, and a non-heat-conducting covering for the edges of said sheetsand the spaces therebetween.

23. A thermal insulation unit which comprises 4, a plurality ofmetallicsheets of suificient thickness to maintain preformed shapeand-formed of a material possessing relatively low reflectivecharacteristics when exposed to radiation of wave lengths within thevisible portion of the electromagnetic spectrum. and relatively highreflective 60 characteristics when exposed to radiation of longer wavelengths than the visible portion of the electromagnetic spectrum, meanssecured: to said sheets at spaced points to space said sheetspredetermined distances with respect to each 35 other and the wallsurfaces defining the space to be insulated; and separate meansenclosing the edges of said sheets and sealing the spaces formed by saidshe ts apart from each other.

24. A thermal insulation unit which comprises a plurality of stiffspaced metallic sheets of sim ilar shape and decreasing progressively inoutline dimensions from one of the outermost sheets to the otheroutermost sheet, spacin members secured to said sheets at spaced pointsaround the aoimsi edges of the latter to secure said sheets together inpredetermined spaced relation and to form a miter-shaped unit, and meanscovering the sides of the unit and secured to the edges of said sheetsfor sealing the spaces between said sheets.

25. A thermal insulation unit comprising a plurality of metallic sheetsand of sumcient thickness and stiffness to retain pre-formed shape, theouter of which are adapted to engage surfaces of the space to beinsulated, spacing members of a length substantially equal to the widthof the unit connected to said sheets at spaced points around said sheetsfor holding the latter as a. unit in predetermined spaced relation withrespect to each other, and a relatively thin covering of substantiallythe width of the unit secured around the edges of said sheets fortherebetween.

26. A thermal insulation unit comprising a plurality of relatively stiifmetallic sheets normally of relatively high heat conduction capacity,the outer of which are adapted to engage surfaces of the space to beinsulated, spacing members formed oi a material of relatively low heatconduction capacity and of a length substantially equal to the width ofthe unit connected to said sheets at spaced points around said sheetsfor holding the ealing the air spaces for sealing the air spacestherebetween, said means being secured to said flanges and to saidmembers. A

28. A thermal insulation unit comprising a plurality of stiif spacedmetallic sheets, spacing members located at spaced points around saidsheets,

said members having sheet-supporting elements 20 thereon which arespaced apart to predetermined extents, said sheets being seated upon andsecured to said elements, and a cover member extendin over the edges 01'said sheets substantially throughout the width of the unit for sealingthe 25 spaces between said sheets apart from each other.

JOSEPH M. LE GRAND.

